Hepatitis

 

🦠 COMMONLY OCCURRING COMMUNICABLE DISEASES

HEPATITIS

🔹 INTRODUCTION

Hepatitis refers to inflammation of the liver resulting in injury to liver cells.

It can be caused by:

• Toxins
• Certain drugs
• Alcohol abuse
• Bacterial infections
• Viral infections

The term hepatitis also refers to a group of viral infections affecting the liver, mainly:

• Hepatitis A (HAV)
• Hepatitis B (HBV)
• Hepatitis C (HCV)
• Hepatitis D (HDV)
• Hepatitis E (HEV)

These account for the majority of hepatitis cases worldwide.

🔹 TYPES OF VIRAL HEPATITIS

Common viruses causing hepatitis:

• HAV, HBV, HCV, HDV, HEV (major causes ~95%)
• Others:
• Herpes simplex virus
• Cytomegalovirus
• Epstein–Barr virus
• Yellow fever virus
• Adenovirus

🔹 ETIOLOGY (CAUSES)

Major causes include:

• Use of infected needles/syringes
• Intravenous drug abuse
• Transfusion of infected blood/products
• Unprotected sexual contact
• Poor sanitation and contaminated food/water

🔹 MODES OF TRANSMISSION

Virus	Source	Transmission Route
HAV	Feces	Fecal–oral
HBV	Blood/body fluids	Parenteral, sexual
HCV	Blood	Parenteral
HDV	Blood	Parenteral
HEV	Feces	Fecal–oral

🔹 HEPATITIS A (HAV)

Causes

• Contaminated food and water
• Raw shellfish from polluted water
• Poor sanitation

Features

• Highly contagious
• Acute infection only (no chronic disease)
• Full recovery is common

Virus Characteristics

• Small, non-enveloped RNA virus
• Replicates in cytoplasm

Pathophysiology

• Enters via oral route
• Travels to liver → infects hepatocytes
• Liver damage occurs due to:
• Direct viral effect
• Immune response

🔹 HEPATITIS B (HBV)

Causes

• Blood transfusion
• Needle sharing
• Sexual transmission
• Perinatal transmission

Features

• Can be acute or chronic
• May lead to:
• Cirrhosis
• Hepatocellular carcinoma

Virus Characteristics

• DNA virus (Hepadnavirus)
• Replicates via reverse transcription

Important Antigens

• HBsAg → Surface antigen
• HBcAg → Core antigen
• HBeAg → High infectivity marker

Pathophysiology

• Virus itself does not destroy cells
• Liver damage due to immune response (T-cells)
• Chronic infection → weak immune response

🔹 HEPATITIS C (HCV)

Causes

• Blood transfusion
• Needle sharing
• Mother-to-child transmission
• Sharing personal items (razors, toothbrushes)

Features

• Often asymptomatic
• High chance of chronic infection
• May lead to:
• Cirrhosis
• Liver cancer

Virus Characteristics

• RNA virus (Flaviviridae family)

Pathophysiology

• Targets hepatocytes
• Persistent infection → chronic inflammation → fibrosis

🔹 HEPATITIS D (HDV)

Key Point

• Requires HBV for replication

Types

1.     Co-infection (HBV + HDV together)

• Usually self-limiting
• Rare chronic infection

2.     Superinfection (HDV in HBV carrier)

• Severe disease
• Rapid progression to cirrhosis
• High risk of liver failure

Pathophysiology

• Severe immune-mediated liver damage

🔹 HEPATITIS E (HEV)

Causes

• Contaminated water (endemic areas)
• Undercooked pork (non-endemic areas)

Features

• Acute infection
• Dangerous in pregnant women

🔹 HDV SUPERINFECTION IN HBV

• Occurs in chronic HBV patients
• Leads to:
• Acute flare of hepatitis
• Rapid disease progression
• Cirrhosis within 2 years (10–15% cases)

Diagnosis Tip

• IgM anti-HBc helps differentiate:
• High → Acute HBV
• Low/negative → Chronic HBV

🔹 PREVENTION

• Vaccination (HBV, HAV)
• Safe blood transfusion
• Use sterile needles
• Safe sex practices
• Clean drinking water
• Proper hygiene

🔹 IMPORTANT EXAM POINTS ⭐

• HAV & HEV → Fecal-oral
• HBV, HCV, HDV → Blood-borne
• HDV requires HBV
• HCV → highest chronicity
• HBV → vaccine available
• HEV → severe in pregnancy

🦠 INFECTION WITH HDV AFTER HBV (SUPERINFECTION)

When a patient already has chronic Hepatitis B, exposure to Hepatitis D can lead to superinfection.

🔹 Key Features

• Occurs in chronic HBV carriers
• Causes acute flare of hepatitis
• Often misdiagnosed as acute HBV infection

🔹 Diagnosis Tip

• IgM anti-HBc levels
• High → Acute HBV
• Low/negative → Chronic HBV (suggests HDV superinfection)

🔹 Clinical Course

• Severe and rapidly progressive
• Leads to:
• Chronic hepatitis
• Cirrhosis (10–15% within 2 years)

🔹 Important Points

• HDV suppresses HBV replication
• In HBV + HDV + Hepatitis C:
• HCV replication is reduced

🦠 HEPATITIS E (HEV)

🔹 Overview

• Caused by Hepatitis E virus
• Usually acute and self-limiting
• Does not commonly cause chronic infection (except in immunocompromised)

🔹 Transmission

• Fecal–oral route
• Contaminated water
• Undercooked pork (non-endemic areas)

🔹 High-Risk Groups

• Pregnant women (severe disease)
• Organ transplant patients
• HIV patients

🔹 Virus Structure & Pathophysiology

• RNA virus (Hepevirus genus)
• Non-enveloped, icosahedral
• Genome:
• ORF-1 → replication proteins
• ORF-2 → capsid protein
• ORF-3 → function unclear

🔹 Genotypes

• Genotype 1 & 2 → Humans
• Genotype 3 & 4 → Zoonotic

🦠 HEPATITIS G (GBV-C)

🔹 Overview

• Also called GB virus C (GBV-C)
• Belongs to Flaviviridae family

🔹 Key Fact

• Infects humans but does NOT cause significant disease

🔹 Structure

• Enveloped RNA virus
• Similar to HCV (~25% homology)

🔹 Replication

• Occurs mainly in:
• Lymphocytes (CD4, CD8, B cells)
• Low levels in liver

🦠 SYMPTOMS OF VIRAL HEPATITIS

🔹 Common Symptoms

• Nausea and vomiting
• Loss of appetite
• Fatigue and weakness
• Fever
• Dark urine
• Pale stools
• Jaundice
• Abdominal pain

🔹 Hepatitis-Specific Symptoms

🟢 Hepatitis A

• Usually mild
• Rare: acute liver failure (elderly, chronic liver disease)

🔵 Hepatitis B

·        Often asymptomatic in children

·        Chronic cases →

• Cirrhosis
• Liver failure
• Kidney problems

·        Co-infection with HDV → severe complications

🟠 Hepatitis C

·        Chronic disease symptoms:

• Fatigue
• Weight loss
• Muscle & joint pain
• Depression
• Cognitive issues

·        Advanced (cirrhosis):

• Ascites
• Bleeding tendency
• Hepatic encephalopathy

🔴 Hepatitis D

• Similar to HBV
• More severe disease
• Can worsen HBV symptoms

🟡 Hepatitis E

• Malaise
• Arthritis
• Pancreatitis
• Neurological complications:
• Guillain-Barré syndrome
• Bell’s palsy
• Neuropathy

🧪 DIAGNOSIS

🔹 Blood Tests

Detect antibodies against hepatitis viruses.

🔹 Liver Function Tests (LFTs)

• ALT (SGPT)
• AST (SGOT)
• ALP
• GGT

🔹 Acute Viral Hepatitis Panel

Includes:

• HAV IgM → Acute HAV
• HBc IgM → Acute HBV
• HBsAg → Current HBV infection
• HCV antibody → Exposure (not active vs past)

🔹 Additional Tests

• HBV surface antibody → Immunity
• HDV antibody & RNA → HDV infection
• HEV IgM → Acute HEV
• GBV-C RNA → Detection via PCR

🔹 Liver Biopsy

Used to:

• Assess liver damage
• Stage hepatitis B & C
• Guide treatment

💊 TREATMENT

🟢 Hepatitis A

• No specific treatment
• Supportive care only

🔵 Hepatitis B

Acute:

• Usually self-limiting

Chronic:

Antiviral drugs:

• Lamivudine
• Entecavir
• Adefovir
• Telbivudine

Other:

• Interferon therapy

Severe Cases:

• Liver transplantation

Prevention:

• Vaccination (HBsAg-based vaccine)

🟠 Hepatitis C

Treatment Goal:

• Complete viral cure

Drugs:

• Sofosbuvir + Ledipasvir
• Sofosbuvir + Simeprevir
• Ribavirin ± Interferon

Important:

• No vaccine available

🔴 Hepatitis D

• Interferon-alpha (long-term)
• No specific vaccine
• Prevent by HBV vaccination

🟡 Hepatitis E

• Mostly supportive treatment
• Ribavirin in severe cases
• Pegylated interferon in chronic cases

🛡️ PREVENTION

• Safe drinking water
• Good sanitation
• Personal hygiene
• Avoid contaminated food
• Safe sex practices
• Sterile needles
• Vaccination (HBV, HAV)

⭐ HIGH-YIELD EXAM POINTS

• HDV needs HBV (most important MCQ)
• Superinfection > Co-infection severity
• HEV severe in pregnancy
• HCV → highest chronicity
• HBV → vaccine available
• GBV-C → non-pathogenic